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WRF-Chem "WARNING: Large total optical depth of ..."

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Rui_Silva

New member
Dear all,

I am using WRF-Chem V3.9.1 to simulate the direct and indirect effects of a Saharan dust event. However, WRF-Chem is filling my rsl.error and rsl.out files with the following warning after 9 hours into the simulation (even with debug_level set to zero):

WARNING: Large total optical depth of 5.15 at point i,j,ib= 56 2 1
Diagnostics 1: k, tauaer300, tauaer400, tauaer600, tauaer999
1 0.01 0.01 0.01 0.01
2 0.01 0.01 0.01 0.01
3 0.02 0.02 0.02 0.01
4 0.02 0.02 0.02 0.01
5 0.03 0.03 0.03 0.01
(...) (...) (...) (...) (...)


I am using HTAP2 anthropogenic emissions, FINNV1.5 fire emissions, Megan biogenic emissions, and MOZART-4/GEOS-5 initial and boundary conditions, all speciated for RADM2/SORGAM.
I did several test simulations (1-day simulations), turning off each of the emissions, and found that this warning disappears when I turn off the chem_in_opt and have_bcs_chem. This is a strange warning, since I don't see anything wrong with the initial and boundary conditions fields and with my wrfouts fields. Below are some of my namelist.input options:

==========================================================================================================
&time_control
run_days = 0,
run_hours = 0,
run_minutes = 0,
run_seconds = 0,
start_year = 2012,
start_month = 06,
start_day = 20,
start_hour = 00,
start_minute = 00,
start_second = 00,
end_year = 2012,
end_month = 06,
end_day = 21,
end_hour = 00,
end_minute = 00,
end_second = 00,
interval_seconds = 21600
input_from_file = .true.,
history_interval = 180,
frames_per_outfile = 1,
restart = .false.,
restart_interval = 1440,
io_form_history = 2
io_form_restart = 2
io_form_input = 2
io_form_boundary = 2
debug_level = 0
history_outname = "wrfout_d<domain>_<date>"
io_form_auxinput4 = 2
auxinput4_inname = "wrflowinp_d<domain>"
auxinput4_interval = 360,
ignore_iofields_warning = .true.
!iofields_filename = "myoutfields.txt",
auxinput5_inname = 'wrfchemi_d<domain>_<date>',
auxinput6_inname = 'wrfbiochemi_d<domain>',
auxinput7_inname = 'wrffirechemi_d<domain>_<date>',
io_form_auxinput5 = 2, ! Anthropogenic Emissions input file format
io_form_auxinput6 = 2, ! Biogenic Emissions input file format
io_form_auxinput7 = 2, ! Fire/Biomass Burning Emissions input file format
auxinput5_interval = 360, ! Interval in minutes between Anthropogenic Emissions input files
auxinput6_interval = 90000, ! Interval in hours between Biogenic Emissions input files
auxinput7_interval = 60, ! Interval in minutes between Fire/Biomass Burning Emissions input files
frames_per_auxinput5 = 1, ! Number of time frames inside each Anthropogenic Emissions input file
frames_per_auxinput6 = 12, ! Number of time frames inside each Biogenic Emissions input file
frames_per_auxinput7 = 1, ! Number of time frames inside each Fire/Biomass Burning Emissions input file
!nocolons = .true.,
/

&domains
!use_adaptive_time_step = .false.,
!step_to_output_time = .true.,
!target_cfl = 1.2,
!max_step_increase_pct = 5,
!starting_time_step = -1,
!max_time_step = -1,
!min_time_step = -1,
!adaptation_domain = 1,
time_step = 72, !108,
!time_step_fract_num = 0,
!time_step_fract_den = 1,
max_dom = 1,
e_we = 374,
e_sn = 260,
dx = 18000,
dy = 18000,
e_vert = 60,
p_top_requested = 5000,
num_metgrid_levels = 38,
num_metgrid_soil_levels = 4,
grid_id = 1,
parent_id = 1,
i_parent_start = 1,
j_parent_start = 1,
parent_grid_ratio = 1,
parent_time_step_ratio = 1,
feedback = 0,
smooth_option = 0,
sfcp_to_sfcp = .false.,
use_surface = .false.,
/


&physics
mp_physics = 2,
ra_lw_physics = 4,
ra_sw_physics = 2,
radt = 18,
sf_sfclay_physics = 1,
sf_surface_physics = 2,
bl_pbl_physics = 1,
bldt = 0,
cu_physics = 5,
cudt = 0,
isfflx = 1,
ifsnow = 0,
surface_input_source = 1,
num_soil_layers = 4,
sf_urban_physics = 0,
seaice_threshold = 0.0,
fractional_seaice = 1,
sst_update = 1,
num_land_cat = 33,
cu_rad_feedback = .true.,
cu_diag = 1,
progn = 1,

&chem
chem_opt = 41,
chem_in_opt = 1,
io_style_emissions = 2,
chemdt = 1.2,
bioemdt = 1.2,
kemit = 1,
photdt = 1.2,
phot_opt = 2,
emiss_opt = 3,
gas_drydep_opt = 1,
aer_drydep_opt = 1,
bio_emiss_opt = 2,
ne_area = 200,
emiss_inpt_opt = 1,
biomass_burn_opt = 2,
plumerisefire_frq = 60,
dust_opt = 3,
seas_opt = 0,
dmsemis_opt = 0,
aer_op_opt = 1,
opt_pars_out = 1,
gas_bc_opt = 16,
gas_ic_opt = 16,
aer_bc_opt = 1,
aer_ic_opt = 1,
gaschem_onoff = 1,
aerchem_onoff = 1,
wetscav_onoff = 1,
cldchem_onoff = 1,
chem_conv_tr = 1,
vertmix_onoff = 1,
conv_tr_wetscav = 1,
conv_tr_aqchem = 1,
have_bcs_chem = .true.,
aer_ra_feedback = 1,
=========================================================================================================

Can someone tell me why this is happening?
My rsl.error files have ~2Gb after 24 hours of simulation.


Thank you!


Kind regards,
Rui Silva
 
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